Characteristics of alternating currents: past paper questions

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• Question 7May/June 2026, paper 41Structured8 marksHas a diagram

  State what is meant by half-wave rectification of an alternating current.

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• Question 7Oct/Nov 2025, paper 42Structured8 marksHas a diagram

  An alternating voltage $V$ varies with time $t$ according to $$V=18\cos 40\pi t$$ where $V$ is in $\text{V}$ and $t$ is in $\text{s}$. For the alternating voltage: show that the period is $0.050\text{ s}$

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• Question 8Oct/Nov 2024, paper 42Structured9 marksHas a diagram

  State what is meant by the frequency of an alternating current.

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• Question 7Oct/Nov 2023, paper 41Structured8 marksHas a diagram

  A varying current $I$ passes through a resistor of resistance $R$ in the circuit shown in Fig. 7.1. Fig. 7.2 shows the variation with time $t$ of $I$. The current has magnitude $2I_0$ when it is in the positive direction and $I_0$ when it is in the negative direction.

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• Question 8May/June 2026, paper 42Structured7 marksHas a diagram

  A sinusoidal alternating input voltage $V_{\text{IN}}$ is supplied to a circuit that produces a rectified and smoothed output voltage $V_{\text{OUT}}$. The variations with time $t$ of $V_{\text{IN}}$ and $V_{\text{OUT}}$ are shown in Figure 8.1 and Figure 8.2 respectively.

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• Question 6May/June 2025, paper 41Structured12 marksHas a diagram

  Fig. 6.1 shows a circuit that rectifies an alternating input voltage $V_{\mathrm{I}\mathrm{N}}$ and produces an output voltage $V_{\mathrm{O}\mathrm{U}\mathrm{T}}$ across a resistor $R$.

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• Question 7May/June 2024, paper 41Structured10 marksHas a diagram

  A circuit contains a power supply that provides a sinusoidal alternating input voltage $V_{\mathrm{I}\mathrm{N}}$. There is an output voltage $V_{\mathrm{O}\mathrm{U}\mathrm{T}}$ across a load resistor $R$, as shown in Fig. 7.1. Fig. 7.1 State the purpose of the circuit in Fig. 7.1.

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• Question 4Oct/Nov 2023, paper 42Structured11 marksHas a diagram

  An electron in a metal rod moves randomly about a mean position. When an alternating voltage is applied to the ends of the rod, the mean position can be considered to oscillate with simple harmonic motion along the axis of the rod.

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• Question 8May/June 2025, paper 42Structured10 marksHas a diagram

  Fig. 8.1 shows a circuit that produces rectification of an alternating input voltage. The input voltage $V_{\mathrm{I}\mathrm{N}}$ is sinusoidal.

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• Question 6May/June 2025, paper 43Structured12 marksHas a diagram

  Fig. 6.1 shows a circuit that rectifies an alternating input voltage $V_{\text{IN}}$ and produces an output voltage $V_{\text{OUT}}$ across a resistor $R$.

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• Question 7May/June 2023, paper 42Structured10 marksHas a diagram

  Four diodes are used in a bridge rectifier circuit to produce rectification of a sinusoidal a.c. input voltage $V_{\text{IN}}$. Fig. 7.1 shows part of the circuit, but three of the diodes are missing.

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